Fastener driving tool

ABSTRACT

A pneumatically operated automatically cycling fastener driving tool includes a housing having a cavity defining a fluid reservoir. A cylinder is provided in the housing for slidably receiving a piston therein. A cylinder valve is provided for controlling the admission of fluid through and the exhaustion of fluid from the one end of the cylinder in response to the exhaustion of fluid from the cylinder valve and the admission of fluid thereto. A return fluid chamber provides for the return stroke of the piston and communicates with the cylinder. Suitable valve means are provided for supplying fluid to the return fluid chamber when the piston is near the end of its drive stroke. Control means are provided for cycling the fluid between the cylinder valve and the return fluid chamber to provide for repetitive cycling of the fastener driving tool.

United States Patent Ramspeck [4 1 Aug. 15, 1972 [54] FASTENER DRIVING TOOL 3,496,835 2/ 1970 Siegmunn ..91/300 72 I v to 1 H d B. Ran.Is k 3,552,270 Lange ..9l/309 1 n r 3,278,104 10/1966 Becht et a1 ..91 220 [73] Assignee: Fastener Corporation, Franklin Park, Primary Examiner-Paul E. Maslousky [22] Filed, June 25, 1970 Attorney-Mason, Kolehmajnen, Rathburn & Wyss PP N 56,062 [57] ABSTRACT Related US. Application Data A pneumatically operated automatically cycling fastener driving tool includes a housing having a cavity defining a fluid reservoir. A cylinder is provided in the housing for slidably receiving a piston therein. A cylinder valve is provided for controlling the admission of fluid through and the exhaustion of fluid from the one end of the cylinder in response to the exhaustion of fluid from the cylinder valve and the admission of fluid thereto. A return fluid chamber provides for the return stroke of the piston and communicates with the cylinder. Suitable valve means are provided for supplying fluid to the return fluid chamber when the piston is near the end of its drive stroke. Control means are provided for cycling the fluid between the cylinder valve and the return fluid chamber to provide for repetitive cycling of the fastener driving tool.

7 Claims, 5 Drawing Figures PATENTEDmms I972 3.683.746

FIG. 4

FIG. 5

0 (5 no I INVENTORI HUM/4RD 5. RAMS [CK ATT'YS FASTENER DRIVING TOOL The present application is a continuation of application Ser. No. 708,330, filed Feb. 26, 1968.

This invention relates to a fastener driving tool and, more particularly, to a fastener driving tool including new and improved control means providing for successive or repetitive fastener driving operations upon a single depression of the tool trigger.

Commercially available pneumatic fastener driving tools in the past have frequently provided for a single fastener driving stroke upon each depression of the tool trigger. However situations have arisen where it is desirable to drive a plurality of fasteners in successive fastener driving operations at suitably short intervals upon a single depression of the tool trigger.

An object of the present invention therefore is to provide a new and improved pneumatically actuated fastener driving tool of the type to continuously and repetitively operate through its working cycle so long as the trigger thereof is depressed.

Another object of the present invention is to provide a fastener driving apparatus having new and improved control means.

Yet a further object of the present invention is the provision of the fastener driving tool of the type wherein the tool will repetitively and continuously operate through its working cycle so long as the trigger member is depressed, and wherein the rate of recycling of the tool may readily by varied.

Further objects and advantages of the present invention will become apparent as the following description proceeds and the features of novelty which characterize the invention will be pointed out with particularity in the claims annexed to and forming a part of this specification.

In accordance with these and other objects there is provided a new and improved automatically cycling fastener driving tool. A known type of commercially available fastener driving tool includes a housing having a cavity defining a fluid reservoir and containing a cylinder in the housing slidably receiving a piston therein. A cylinder valve is provided for controlling the admission of fluid to and the exhaustion of fluid from one end of the cylinder. A return fluid chamber in the housing communicates with the cylinder and is effective to move the piston through its return stroke. In accordance with the present invention control means are provided for cycling the fluid between the cylinder valve and the return fluid chamber to obtain repetitive and successive firing or cycling of the fastener driving tool. In a preferred embodiment the trigger control of the fastener driving tool functions as a three way valve, so that in its released position the cylinder valve is connected with the fluid reservoir, but in its operated or depressed position the cylinder valve is connected with the return fluid chamber. If desired, a metering needle assembly may be inserted in the passageway between the return fluid chamber and the cylinder valve to regulate the rate or speed of recycling of the fastener driving tool.

Many other objects and advantages of the present invention will become apparent from considering the following detailed description in conjunction with the drawings in which:

FIG. 1 is a fragmentary cross sectional view of a fastener driving tool incorporating the present invention and illustrated with the drive piston in its static or rest position;

FIG. 2 is a fragmentary cross sectional view of the fastener driving tool of FIG. 1 illustrated with the trigger depressed and the drive piston at the end of its drive stroke;

FIG. 3 is a fragmentary cross sectional view of the improved fastener driving tool of FIG. 1, illustrated with the piston moving through its return stroke;

FIG. 4 is a fragmentary cross sectional view of the improved fastener driving tool taken through the needle valve substantially along line 44 of FIG. 4;

FIG. 5 is a fragmentary cross sectional view illustrating the needle valve in another of its selectively adjustable positions; and

FIG. 6 is a fragmentary cross sectional view illustrating the control or trigger valve of the fastener driving tool of FIG. 1.

Referring now to the drawings, there is fragmentarily illustrated a fastener driving too] generally as 10, which embodies a trigger or control valve assembly and auto fire connection according to the present invention. The tool 10 may be of generally known construction, and, as illustrated, is similar to that described in the copending application Ser. No. 602,728 filed Dec. 19, 1966 by Richard H. Doyle, and comprises a housing 12 including a generally vertically extending head or forward portion 12a and a rearwardly extending hollow handle portion 12b defining a fluid reservoir 16. Pressurized fluid such as compressed air is supplied to the fluid reservoir of the tool 10 by a suitable flexible line. The drive system for the tool 10 includes a main or power cylinder 18 mounted within the head portion 12a having an open upper end 18a that is adapted to be selectively connected to the reservoir 16. The open upper end of the cylinder 18 is in engagement with a diaphragm type main or cylinder valve assembly 20, here shown of the poppet type, under the control of a control or trigger valve assembly 22 according to the present invention. A fastener driving assembly 24 slideably mounted within the cylinder 18 includes a work or drive piston 26 and has connected thereto a depending driver blade member 28. The fastener driving assembly 24 is normally biased to a position with the piston 26 adjacent the cylinder valve assembly 20, as illustrated in FIG. 1. An exhaust valve assembly in dicated generally as 32 is provided for controlling the selective connection of the upper end of the cylinder 18 to the atmosphere.

When the tool 10 is to be operated, compressed fluid from the reservoir 16 enters the upper open end 18a of the cylinder 18 and drives the fastener driving assembly 24 downwardly to engage and set a fastener or nail supplied to a drive track 36 in a nosepiece and nosepiece structure 38. The flow of compressed fluid into the upper end of the cylinder 18 is controlled by the cylinder valve assembly 20, which includes a diaphragm 40, the periphery of which is clamped between a cap 42 and the head portion 12a of the housing 12 which seats against the upper edge 18a of the cylinder 18. The diaphragm 40* is resiliently biased against the upper edge surface 18by a spring 44 located between the cap 42 and the diaphragm 40. The cylinder side of the diaphragm 40 is continuously in communication with the fluid reservoir 16 through a suitable passageway 46 so that pressurized fluid continuously acts against the cylinder side of the diaphragm 40 tending to displace the diaphragm 40 from the edge 18a of the cylinder 18. However pressurized fluid is also introduced to a control chamber 47 at the opposite side of the diaphragm 40 through a passageway 48 while the fastener driving tool is in a static or at rest position. The pressure in the control chamber 47 acting above the diaphragm 40 is effective to maintain the diaphragm 40 in a closed position, as illustrated in FIG. 1. However if the pressurized fluid above the diaphragm 40 is discharged, the pressurized fluid through the passageway 46 is then effective to unseat the diaphragm 40 from the edge 18a of the cylinder 18 to dump pressurized fluid into the top of the main cylinder 18 and to drive the drive piston 26 through a drive stroke.

When the fastener driving tool is at rest, or during the return stroke of the drive piston, the open upper end of the cylinder 18 is exhausted to the atmosphere through the exhaust valve assembly 32. In the illustrated embodiment the exhaust valve assembly 32 comprises a hollow valve stem 50 secured to the diaphragm connecting the upper end of the cylinder to the atmosphere through a suitable exhaust passageway 52. However when the drive piston is operated through a fire or drive stroke, it is necessary for the upper end of the cylinder 18 to be closed, and to this end there is provided a valve seat 54 disposed adjacent the end of the valve stem 50 remote from the cylinder 18 adapted to be engaged by the valve stem 50 when the diaphragm 40 is raised at the initiation of a drive stroke, thereby closing off the upper end of the cylinder 18 to the atmosphere.

To provide for the return drive of the fastener driving assembly 24, there is provided an air return chamber 60 communicating with the lower end of the cylinder 18 through a plurality of ports 62. Moreover the drive piston 26 is provided with suitable one way valve means 63. To this end the piston 26 is provided with spaced peripheral grooves 64 and 66, the upper one of which serves as a sealing groove while the lower one 66 functions as the one way valve means 63 to provide for the bypass of pressurized fluid to the air return chamber 60. An O-ring 68 provided in the upper one of the grooves 64 functions as a sealing member effecting a pneumatic seal between the piston 26 and the inner wall of the cylinder 18. To bypass around the groove 64 and O-ring 68, there is provided a plurality of air passageways 70 extending from the lower one 66 of the grooves and communicating with a central cavity 26a in the piston 26. An O-ring 72 defining a valve element is positioned within the lower one 66 of the grooves. The O-ring 72 is expandable upon a selected pressure differential between the upper and lower ends of the cylinder through the piston 26 so as to unseat from the ports of the air passageways 70 to provide for fluid to bypass through the piston 26 around the O-ring 72 and to supply air to the air return chamber 60.

It will be understood that in the operation of the basic tool the piston 26 and associated driver blade member 28 is driven downwardly through a drive stroke by connection of the open upper end 18a of the cylinder 18 with the reservoir 16. Since there is no significant restraint to the piston during its downward movement, the pressure above the piston 26 will not build up sufficiently to unseat the O-ring 72 until the piston 26 approaches the bottom of its drive stroke. At this point the pressure above the piston 26 will continue to build up until it approaches the pressure in the reservoir 16 and the O-ring 72, functioning as a valve element, will be unseated from the ports of the air passageways 70, thereby providing a source of pressurized fluid to the air return chamber 60 through the air passageway 62.

To cushion the drive stroke of the piston 26, and to seal the lower end of the cylinder 18 when the piston 26 is at its lowermost position, there is provided a resilient annular bumper 74 at the lower end of the cylinder 18 which is engageable by the piston 26 as it is atthe end of its drive stroke. Air from the lower end of the cylinder normally vents through a blade opening 76 in a washer 78 at the lower end of the bumper 74. However when the piston 26 engages the bumper 74 as illustrated in FIG. 2, pressurized fluid which passes around the O-ring 72 cannot vent to atmosphere through the blade opening 76. Upon exhaustion of the open upper end 18a of the cylinder 18 to the atmosphere, the pressurized fluid in the air return chamber 60 will reenter the lower end of the cylinder 18 through the port 62 and will drive the piston 26 back to its normal or at rest position. Leakage of air around the blade opening 76 is not rapid enough to prevent the return of the piston 26.

The trigger valve assembly 22 controls the admission of fluid to, and the exhaustion of fluid from the cylinder valve assembly 20. More specifically, the trigger valve assembly 22 includes a valve chamber 80 connecting at its upper end with the reservoir 16 through a port 82a at the upper end of a passageway 82 whose lower end terminates in a valve port 82b opening into the valve chamber 80. The valve port 82 terminates the illustrated vertical passageway which has an upper port coupling this passageway to the reservoir 16. A valve port 84 in the side of the valve chamber 80 connects through the passageway 48 with the cylinder valve assembly 20. The valve chamber 80 is open at its lower end and is fitted with a valve sleeve 86 sealed to the walls of the valve chamber 80 by an O-ring 88, FIG. 6. A valve element or ball 90 is contained within the valve chamber 80, alternately seatable against the valve port 82b and against an O-ring 92 defining a valve seat. A trigger valve stem 94 extends through the sleeve 86 for actuating the valve ball 90. An O-ring 96 forms a seal between the valve stem 94 and the sleeve 86.

A passageway 98 interconnects the air return chamber 60 and the trigger valve assembly 22, opening with a port 100 extending through the valve sleeve 86. A reduced diameter portion 94a on the valve stem 94 defines a passageway 94b, FIG. 6, placing the port 100 in communication with the valve chamber 80 when the valve ball 90 is raised from the valve seat 92, as illustrated in FIGS. 2 and 3. A trigger member 102 pivotally mounted to the housing 12 provides for unseating of the ball valve 90 from the valve seat 92 and for engagement with the port 82b to block off communication of the valve chamber 80 with the reservoir 16.

To provide for metering the fluid flow through the passageway 98, thereby regulating the rate of recycling of the tool 10, there is provided a needle valve member 106 adjustably threaded within an opening 108, FIGS.

4 and 5, of the housing 12 and provided with a tapered portion 106a which may be withdrawn from obstruction of the passageway 98, as illustrated in FIG. 4, and which may be selectively projected into the passageway 98 to provide throttling of the fluid flow therethrough, as illustrated in FIG. 5.

From the above description of the improved fastener driving tool its operation is believed clear. Briefly, however, with the fastener driving tool 10 at rest, as illustrated in FIG. 1, the cylinder valve is maintained closed by the fluidized pressure which enters above the diaphragm 40 through the passageway 48, valve chamber 80, and valve port 82 from the reservoir 16. Upon depression of the trigger 102 and reciprocation of the valve ball 90 from the valve seat 92 against the port 82b, the pressurized fluid in the control chamber 47 above the diaphragm 40 will bleed through the passageway 48, the valve chamber 80, around the reduced diameter portion 94a of the valve stem 94, through the port 100 and the passageway 98 into the air return chamber 60, through the ports 62 into the lower end of the cylinder 18, and through the blade opening 76 to the atmosphere. In this position, as illustrated in FIG. 2, the diaphragm 40 will be raised from the engagement with the upper edge 18a of the cylinder 18 and fluid from the reservoir 16 will be dumped into the upper end of the cylinder 18. At the same time the valve stem 50 will move upwardly against the valve seat 54 to block exhaust of the upper end of the cylinder 18. The pressurized fluid dumped into the upper end of the cylinder 18 will now be effective to drive the piston 26 downwardly through a drive stroke.

As soon as the piston 26 reaches the bottom of its drive stroke, as illustrated in FIG. 2, the pressure above the piston 26 will build up sufficiently to unseat the O- ring 72 forming a valve member and permit bypass of fluid from the cylinder 18 through the passageways 70 and into the air return chamber 60 through the ports 62. As the pressure in the air return chamber 60 continues to build up, the fluid will flow through the passageway 98, the port 100, around the reduced diameter portion 94a of the valve stem 94 into the valve chamber 80, and through the passageway 48 into the chamber 47 above the diaphragm 40. As soon as the differential pressure on the diaphragm 40 is suffrcient to close the diaphragm 40, the diaphragm 40 will move downwardly to move the valve stem 50 away from the valve seat 54 and place the exhaust passageway 52in communication with the upper end of the cylinder 18. At the same time the pressurized fluid within the air return chamber 60 will act below the piston 26 to move the piston upwardly through its return stroke, as illustrated in FIG. 3.

As soon as the piston 26 begins its return stroke, so that the piston unseats from the bumper 74 thereby venting the lower end of the cylinder 18 to atmosphere around the blade opening 76, fluid will exhaust from above the diaphragm 40 of the cylinder valve assembly 20. More specifically the air will pass from the chamber 47 the passageway 48, the port 84 into the valve chamber 80, around the reduced diameter portion 940, into the port 100, through the passageway 98 and around the needle valve 106 into the return air chamber 60, through the ports 62, and through the blade opening 76 to the atmosphere. As the piston 26 reaches the end of its return stroke, the differential pressure acting on the diaphragm 40 will be sufficient once again to unseat the diaphragm 40 from the edge 18a of the cylinder 18thereby to dump fluid into the top of the cylinder 18. Thus the piston 26 will be recycled through another driving stroke. Such repetitive recycling of the tool 10 takes place so long as the trigger 102 is depressed.

It will be appreciated that the needle valve 106 throttles the flow of pressurized fluid' from the return air chamber 60 through the cylinder valve assembly 20, and thereby controls the rate of exhaust from the cylinder valve 20, thus adjustably regulating the recycling rate of the tool 10.

There has been provided a fastener driving tool of generally conventional design, except for the addition of the fluid passageway between the return air chamber and the trigger valve, so that the tool will function in a repetitive and continuous manner so long as the trigger 102 is maintained depressed. Moreover the recycling rate of the tool is readily controllable by the needle valve member 106.

What is claimed as new and desired to be secured by Letters Patent of the United States is:

1. A pneumatically operated automatically cycling fastener driving tool including a housing having a cavity defining a fluid reservoir,

a cylinder in said housing,

a piston slidably mounted in the cylinder,

main valve means controlling the admission of fluid to and the exhaustion of fluid from said one end of said cylinder in response to the exhaustion of fluid from one surface of said main valve and the admission of fluid against said surface thereto,

a return fluid chamber in said housing communicating with said cylinder,

valve means for supplying fluid to said return fluid chamber when said piston is near the end of its drive stroke,

passage means interconnecting said surface of said main valve means and said return fluid chamber,

and control valve means operatively associated with said passage means for selectively opening and closing said passage means.

2. A fastener driving tool as set forth in claim 1 including a trigger valve assembly connected when released to interconnect said surface of said main valve means and said reservoir, and connected when depressed to interconnect said surface of said main valve means and said return fluid chamber.

3. A fastener driving tool as set forth in claim 1 ineluding means for throttling the fluid flow between said main valve means and said return fluid chamber thereby regulating the rate of recycling of said tool.

4. A pneumatically operated fastener driving tool including a housing having a cavity defining a fluid reservoir,

a cylinder in said housing,

a piston slidably mounted in the cylinder and provided with fluid bypass means for one end of said cylinder to the other end thereof upon a predetermined pressure differential,

main valve means controlling the admission of fluid to and the exhaustion of fluid from said one end of said cylinder in response to the exhaustion of fluid from one surface of said main valve means and the admission of fluid to said surface thereto,

a return fluid chamber in said housing communicating with said other end of said cylinder,

means for exhausting said other end of said cylinder,

and trigger control means connecting said surface of said main valve means to said reservoir when released and connecting said surface of said main valve means to said return air chamber when depressed.

5. A fastener driving tool as set forth in claim 4 including means for throttling the fluid flow between said surface of said main valve means and said return fluid chamber thereby regulating the rate of recycling of said tool.

6. An automatically cycling fastener driving tool comprising:

a housing including a cylinder and a reservoir supplied with fluid under pressure;

a fastener driving means including a piston slidably mounted in the cylinder;

main valve means movable between normal and operated positions to selectively connect the cylinder to the atmosphere and the fluid in the reservoir;

operating means connected to the main valve means for controlling movement of the main valve means between its normal and operated positions, said operating means including a fluid pressure control chamber and a fluid pressure responsive means with a fluid pressure responsive surface; manually controlled valve means having a first passage connected to the control chamber and additional second and third passages said manually controlled valve means having a first position coupling the first and second passages and a second position connecting the first and third passages; first means coupling the second passage to the reservoir so that fluid is applied from the reservoir to said surface when the manually controlled valve means is in its first position; and second means for placing the third passage in communication with the cylinder so that the third passage is alternately connected to pressurized fluid and the atmosphere thereby to connect fluid and the atmosphere to said surface over the first and third passages when the manually controlled valve means is in its second position. 7. The fastener driving tool set forth in claim 6 in which the second means includes an opening communicating with the interior of the cylinder that is selectively connected to the atmosphere or pressurized fluid in dependence on the position of the piston. 

1. A pneumatically operated automatically cycling fastener driving tool including a housing having a cavity Defining a fluid reservoir, a cylinder in said housing, a piston slidably mounted in the cylinder, main valve means controlling the admission of fluid to and the exhaustion of fluid from said one end of said cylinder in response to the exhaustion of fluid from one surface of said main valve and the admission of fluid against said surface thereto, a return fluid chamber in said housing communicating with said cylinder, valve means for supplying fluid to said return fluid chamber when said piston is near the end of its drive stroke, passage means interconnecting said surface of said main valve means and said return fluid chamber, and control valve means operatively associated with said passage means for selectively opening and closing said passage means.
 2. A fastener driving tool as set forth in claim 1 including a trigger valve assembly connected when released to interconnect said surface of said main valve means and said reservoir, and connected when depressed to interconnect said surface of said main valve means and said return fluid chamber.
 3. A fastener driving tool as set forth in claim 1 including means for throttling the fluid flow between said main valve means and said return fluid chamber thereby regulating the rate of recycling of said tool.
 4. A pneumatically operated fastener driving tool including a housing having a cavity defining a fluid reservoir, a cylinder in said housing, a piston slidably mounted in the cylinder and provided with fluid bypass means for one end of said cylinder to the other end thereof upon a predetermined pressure differential, main valve means controlling the admission of fluid to and the exhaustion of fluid from said one end of said cylinder in response to the exhaustion of fluid from one surface of said main valve means and the admission of fluid to said surface thereto, a return fluid chamber in said housing communicating with said other end of said cylinder, means for exhausting said other end of said cylinder, and trigger control means connecting said surface of said main valve means to said reservoir when released and connecting said surface of said main valve means to said return air chamber when depressed.
 5. A fastener driving tool as set forth in claim 4 including means for throttling the fluid flow between said surface of said main valve means and said return fluid chamber thereby regulating the rate of recycling of said tool.
 6. An automatically cycling fastener driving tool comprising: a housing including a cylinder and a reservoir supplied with fluid under pressure; a fastener driving means including a piston slidably mounted in the cylinder; main valve means movable between normal and operated positions to selectively connect the cylinder to the atmosphere and the fluid in the reservoir; operating means connected to the main valve means for controlling movement of the main valve means between its normal and operated positions, said operating means including a fluid pressure control chamber and a fluid pressure responsive means with a fluid pressure responsive surface; a manually controlled valve means having a first passage connected to the control chamber and additional second and third passages said manually controlled valve means having a first position coupling the first and second passages and a second position connecting the first and third passages; first means coupling the second passage to the reservoir so that fluid is applied from the reservoir to said surface when the manually controlled valve means is in its first position; and second means for placing the third passage in communication with the cylinder so that the third passage is alternately connected to pressurized fluid and the atmosphere thereby to connect fluid and the atmosphere to said surface over the first and third passages when the manually controlled valve means is in its second position.
 7. The fastener driviNg tool set forth in claim 6 in which the second means includes an opening communicating with the interior of the cylinder that is selectively connected to the atmosphere or pressurized fluid in dependence on the position of the piston. 